Accumulator charging structure



Aug. 6, 1963 w. H. PEET ACCUMULATOR CHARGING STRUCTURE Filed May 9, 1960 FIG.3.

INVENTOR. WILLIAM HAROLD PEET ATTORNEYS United States Patent 3,100,058 ACCUMULATOR CHARGING STRUCTURE William Harold Feet, 2115 Devonshire Road, Ann Arbor, Mich.

Filed May 9, 1960, Ser. No. 27,830 15 Claims. (Cl. nil-89) This invention relates to charging structures and is a continuation-in-part of my co-pending application Serial No. 753,521 filed August 6, 1958, and now abandoned.

One object of this invention is to provide an improved charging structure for a pressure vessel, and more particularly for an accumulator.

Another object of the invention is to provide a charging structure for a vessel or accumulator which includes a resilient, unapertured, pierceable plug of self-sealing ma terial, the plug being adapted to be penetrated by a hypodermic needle or the like for charging.

A further object of the invention is to provide a charging structure as described in the preceding paragraph, having a member extending over the plug to hold it against outward distortion or displacement under pressure, the member having an aperture for receiving the needle during charging, and a closure for covering the aperture to thereby prevent cold flow of the plug through the aperture.

Still another objective of the invention is to provide a charging structure as described above in which the member for holding the plug against outward displacement is in the form of a disc constructed to rupture at a predetermined pressure to release the pressure, with means for preventing separation of the ruptured disc and plug from the casing of the pressure vessel.

More specifically, it is an object of the invention to provide a disc of the above description which is formed with an annular zone of weakness about the central portion thereof which overlies the plug so that the disc will rupture in the annular zone, and in Which the means for preventing separation of the disc comprises a cylinder, one end of which clamps the margin of the disc outwardly of its annular zone of weakness and the other end of which has an inturned flange for retaining the central portion of the disc in the event of rupture.

Other objects of the invention will become apparent as the following description proceeds, especially when considered with the accompanying drawing, wherein:

FIGURE 1 is an axial sectional view of an accumulator having charging structure constructed in accordance with my invention.

FIGURE 2 is a fragmentary sectional view of the accumulator rotated 90 from the position shown in FIG- URE 1.

FIGURE 3 is an enlargement of the charging structure shown in FIGURE 1.

FIGURE 4 is similar to FIGURE 3 but shows .a modification.

FIGURES 5 and 6 illustrate another modification.

Referring now more particularly to the drawing and especially to FIGURES 1-3, an accumulator is illustrated which has an outer shell or casing 11. The accumulator casing is composed of a rigid elongated cylinder 12 which is formed at one end to provide a radially inwardly extending annular retaining flange 14.

An end header member or plug 18 in the form of an 3,100,58 Patented Aug. 6, 1963 2 aluminum casting of special cross sectional shape is disposed inside the cylinder, being axially restrained by the flange 14. A generally similar opposite end header memher or plug 20 is disposed within the opposite end of the cylinder, being axially restrained by an annular cap 22 threaded on the cylinder and formed with a radially inturned restraining flange 24.

The reference numeral 26 designates an elongated tubular diaphragm of synthetic rubber or like flexible or elastically distortable material such as neoprene, proof against attack by hydrocarbons or other fluid to be handled by the accumulator. For the purpose of clamping and restraining the ends of the diaphragm, the end plugs 18 and 20 are each provided with an annular re cess 28 about their outer end periphery, which recesses receive and clamp against the cylinder 12 and the end flanges 14 and 24 an enlarged annular bead 30 at either end of the diaphragm, thus the interiors of the casing 11 and diaphragm 26 me eifectively sealed fluid tight at their ends.

The reference numeral 3-2 designates an elongated fluid permeable distributor core which is disposed within the tubular diaphragm to inwardly sustain the same, while permitting radial flow of liquid through the core in either direction. The core is of a liquid permeable material to permit the radial flow and may be of the general construction described in the application of which this application is a continuation-in-part. The transverse cross section of the core 32 corresponds to that of the inner ends of the header members or plugs 18 and 20 which directly abut its opposite ends, and the plugs have surfaces which are mildly curved radially and axially outwardly from these abutting zones, to sustain the diaphragm in its innermost position without contact with any sharp surface.

The core is supported by the elongated parallel control members 34 which are provided with a multiplicity of longitudinally extending external flutes 35 along their length. To this end, each of the end plugs or headers is provided with diametrically spaced recesses 36 in its inner shaped end, which recesses receive the ends of the flow control members 34. The flow control members 34 extend through bores in the permeable core. Liquid passages 38 in the plug 18 diverge radially outwardly to the recesses 36 from a centrally threaded passage 40 adapted to receive a liquid fitting, not shown. Accordingly, when the accumulator is connected to a source of pressure at the passage 40, liquid under pressure may flow through the diverging passages and along the external, longitudinal control member flutes 35.

Hydraulic fluid may thus fill the interior of the diaphragm, being connected to a suit-able source at the passage -tl and being free to move radially in and out through the core depending on variations in the pressure of the hydraulic fluid.

The space within the casing surrounding the diaphragm is charged with air under pressure by a novel charging structure 42 best shown in FIGURE 3. As there illustrated, the charging structure comprises a resilient, unapertured, pierce able plug 44 of a suitable self-sealing material such as rubber or the like which is adapted to be penetrated by a hypodermic needle type charging fitting. The plug is shaped to fit within the counterbored hole 47 in the wall of the casing cylinder 12.

be on the order of .010" in diameter.

In order to prevent the plug from being blown out of the opening by the interior gas pressure, an intern-ally threaded adapter ring 50 is welded to the exterior of the cylinder, concentrically of the opening 47, and a centrally apertured metal disc 52 is threaded into the adapter ring. The metal disc has a central conical aperture 54 for receiving the hypodermic needle during charging.

In order to prevent the material of the plug from cold flowing through the aperture 54 under the internal pres sure of the accumulator, a restraining plug 56 is threaded into the adapter ring on top of disc 52, being removable for recharging of the accumulator as desired. The restraining plug has a conical tip 53 shaped to fit closely within the aperture of the disc when the plug is installed as shown, the end of the tap engaging the surface of the pierceable plug 44.

In order to charge the accumulator, the restraining plug 56 is removed and the hypodermic needle is forced through the pierceable plug 44 to the interior space. The period of time that the apenture is open for charging is not of sufiicient duration that the material of the pierceable plug will cold flow therethrough. However, immediately after charging the restraining plug should be reinstalled; otherwise it is only a matter of time before the pierceable plug will cold flow through the charging aperture.

The cross section of the conical charging aperture at its small end is important in view of the relatively high pressures employed in accumulators of this type. If the aperture is too large, the pierceable plug will cold flow in the brief time that the aperture is open for charging. Preferably the aperture at its smallest cross section should The aperture at its smallest cross section may under certain circumstances be increased as high as .012" or .016" in diameter. Nevertheless, a diameter of .010 is prefer-able under most circumstances.

It will be noted that the inner surface of the plug 44 'is flush with the inner surface of the cylinder wall. Thus,

no sharp edges are provided which might cause damage to. the flexible diaphragm of the accumulator.

FIGURE 4 illustrates a charging structure having a modified construction. The charging structure there shown is generally indicated at 60 and comprises a pierceahle plug 62 which is formed of a resilient, unapertured, self-sealing material, such as rubber. The plug has a small diameter portion fitting within an opening 64 in the cylinder 12 and a large diameter portion on the outer side of the cylinder Wall fitting within the internally threaded adapter ring 65 which is welded to the exterior of the casing, concentrically of the opening 64. The disc 66 is disposed within the adapter ring and extends over and bears against the outer end of the plug.

The disc has an outward hollow extension 68 which is in threaded engagement with the adapter ring, and threaded in the hollow extension is a needle 70 formed with a conical tip 72 adapted to fit within the central conical charging aperture 71 in the disc. The aperture in the disc 66 has the same cross sectional dimension as the apenture in the disc shown in the FIGURE 3 construction, and the gas space is charged by removing the needle 70 and inserting the hypodermic needle through the pierceable plug. The pierceable plug would in time cold flow through the charging aperture 71 due to the pressure in the accumulator except for the tip of the needle which fills the aperture and engages end surface of the pierceable plug,

A cap 73! extends over the end of the adapter ring and is threaded thereon as shown. The transverse wall of the cap bears on the open end of the hollow extension of the disc to serve as a retainer.

FIGURES and 6 show another modification. The charging structure there illustrated is generally indicated at '14. The cylinder 12 is formed with an integral radially outward hollow projection which serves as an adapter ring 76. The adapter ring 76 is concentric with respect to the oounterbored opening 78 in the casing which leads to the space to be charged. The pierceable plug 80' of resilient, unapertured, self-sealing material such as rubber or the like, is shaped to fit within the counterbored opening 78 and is maintained in the opening against outward distortion or displacement by a metal rupture disc 82. The rupture disc is slipped into the adapter ring and is supported on an annular shoulder 8'4 about the opening.

The central portion of the disc, designated 86, extends over and bears against the outer surface of the plug. The central portion of the disc is formed with an internal hollow extension 87 which communicates with the central conical charging aperture 90 in the disc, the charging aperture having the same dimensions as described above in connection with the other modifications. The hollow extension is internally threaded and a plug 92 is threaded into the hollow extension, being formed with a conical tip 91 shaped to fit the charging aperture and to bear against the surface of the pierceable plug. A typical charging needle is shown at N.

A retainer cage 94 is provided for the rupture disc, being in the form of a cylinder 96 threaded into the adapter ring with one end thereof bearing against the outer margin of the disc to clamp it in place. The annular Zone separating the outer margin of the disc from its central portion is of reduced cross section as shown at 98 so that the disc will fail under a predetermined pressure within the accumulator. This is provided as a safety measure to prevent the accumulator as a whole from exploding. FIGURE 6 illustrates the charging structure after rupture of the disc.

As shown, the cylindrical portion 96 of the cage is provided with a radially inturned annular flange 100 which is of smaller diameter than the central portion of the disc, thereby serving as a retainer and preventing the ruptured central portion of the disc and the pierceable plug from separating with respect to the accumulator.-

The opening provided by the flange 100 is slightly greater in diameter than the hollow extension of the central portion of the disc to clear the extension 87. The cylindrical wall of the cage is formed with one or more vents 102 to enable the gas pressure to escape from the accumulator after rupture of the disc.

What I claim as my invention is:

1. In an accumulator having a casing, means for charging the interior space of said casing comprising a resilient, unapertured, pierceable plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, a removable rigid disc secured to said casing outwardly of and over said plug to hold the latter against outward distortion or displacement under pressure, said disc having an aperture IlIO receive the needle for charging, and a removable closure for said aperture having a part shaped to enter the aperture and engage the plug, the inner surface of said plug being flush with the inner surface of said casing.

2. In a pressure vessel having a casing, means for charging the interior space of said casing comprising a resilient, unapertured, p-ierceable. plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, a removable rigid disc secured to said casing outwardly of and over said plug to hold the latter against outward distortion or displace ment under pressure, said disc having an aperture (to receive the needle for charging of a diameter on the order of .010 inch, and a removable closure for said aperture having a pointed tip shaped to enter said aperture and engage the plug.

3. The structure as set forth in claim 2 in which said casing has an annular extension about said disc and removable closure with which said disc and removable closure is threadedly engaged.

4. The structure as set forth in claim 2. in which said disc has an outwardly threaded projection and said casing has an annular extension surrounding the projection of said disc and threadedly engaging the same, said projection of said disc having a hollow interior leading to the aperture in said disc and threadedly engaging the removable closure, and a cap threaded on the extension of said casing and extending over the opening therein as a retainer for said disc and closure.

5. In a pressure vessel having a casing, means for charging the interior space of said casing comprising a resilient, unapertured, pierceable plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, a rigid disc secured to said casing outwardly of said plug and having a central portion overlying said plug to hold the latter against outward distortion or displacement under pressure, said disc having an annular zone of weakness about said central portion adapted to rupture under a predetermined pressure in said space so that said plug can be blown out of said opening to release the pressure in said space, and means for preventing separation of the central portion of said disc and plug firom said casing after rupture of said disc and release of the pressure in said space including a retainer on said casing having an aperture to vent the released pressure.

6. The construction as in claim 5 in which said disc has an aperture to receive the needle for charging, and a removable closure carried by said disc and having a part shaped to enter the aperture and engage the plug.

7. In a pressure veseel having a casing, means for charging the interior space of said casing comprising a resilient, unaper-tured, pierceable plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, said casing having an exterior outward annular projection about said opening, a rigid disc within said projection having a central portion overlying said plug to hold the latter against outer distortion :or displacement under pres sure, said disc having an annular zone of weakness about said central portion and within the outer margin thereof adapted to rupture under a predetermined pressure in said space so that said plug can be blown out of said opening to release the pressure in said space, and means tor preventing separation of the central portion of said disc and plug from said casing after rupture of said disc and release of the pressure in said space including a retainer secured within said outward projection having an aperture to vent the released pressure, retainer being in clamping engagement with the outer margin of said disc to lock it securely to the casing.

8. The structure as set forth in claim 7 in which said retainer is in the form of a cylinder one end of which clamps over the outer margin of the disc and the other end of which has an inturned flange engageable with the central portion of the disc atter rupture to prevent the separation of the central portion of the disc and plug from the casing.

9. In a pressure vessel having a casing, means for charging the interior space of said casing comprising a resilient, unapertured, pierceable plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, said casing having an annular outward projection about said opening, a rigid disc said outward projection having a central portion overlying said plug to hold the latter against outward distortion or displacement under pressure, said central portion of said disc having an aperture therein to receive the needle for charging, said central portion of said disc having a hollow outward extension the interior of which leads to said aperture, a valve member removably secured in said hollow extension and having a tip shaped to extend into said aperture and engage the plug to prevent cold flow of the material of the plug through the aperture under the pressure existing in said space, said disc having an annular zone of weakness about said central portion adapted to rupture under a predetermined pressure in said space so that said plug can be blown out of said opening to release the pressure in said space, and means tor preventing separation of the central portion of said disc and plug from said casing after rupture of said disc and release of the pressure in said space including a retainer on said casing having an aperture to vent the released pressure, said retainer being in the form of a cylinder removably secured within the outward projection of said casing, one end of said cylinder hearing against the margin of said disc outwardly of its zone of weakness to clamp it securely to the casing and the other end of which has an inwardly directed flange to be engaged by the central portion of the disc and prevent separation of said central portion and of the plug from the casing, said flange being of a dimension to clear the hollow extension of the disc.

10. The construction as in claim 9 in which said pressure vessel is an accumulator having a diaphragm therein cooperating with a wall of the casing to define said space, said plug extending flush with the inner surface of the casing 11. The construction as in claim 10' in which the aperture in said disc has a minimum diameter on the order of .010.

12. In a pressure vessel having a casing, means for charging the interior space of said casing comprising a resilient, unapertured, pierceable plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, a member secured to said casing outwardly of and over said plug to hold the latter against outward distortion of displacement under pressure, said member having an aperture to receive the needle for charging, and means for closing said aperture.

13. In an accumulator having a casing, means for charging the interior space of said casing comprising a resilient, unapertured, pierceable plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, a member secured to said casing outwardly of and over said plug to hold the latter against outward distortion or displacement under pressure, said member having an aperture to receive the needle for charging, and a removable closure for said aperture having a part shaped to enter said aperture and engage said plug.

14. In a pressure vessel having a casin means for charging the interior space of said casing, comprising a resilient, unapertured, pierceable plug of self-sealing mater-ial, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, a member secured to said casing outwardly of and over said plug to hold the latter against outward distortion or displacement under pressure, said member having an aperture to receive the needle for charging of a diameter on the order of .010 inch, and a removable closure for said aperture having a part shaped to enter said aperture and engage the plug.

15. In a pressure vessel having a casing, means for charging the interior space of said casing comprising a resilient, unapertured, pierceable plug of self-sealing material, said casing having an opening to said space receiving said plug, said plug being adapted to be penetrated by a hypodermic needle or the like for such charging, said casing having an exterior outward annular projection about said opening, a rigid disc Within said projection having a central portion overlying said plug to hold the latter against outer distortion or displacement under pres- 7 sure, said disc having an annular zone of Weakness about said central portion and within the outer margin thereof adapted to rupture under a predetermined pressure in said space so that said plug can be blown out of said opening to release the pressure in said space, means for preventing separation of the central portion of said disc and plug from said casing after rupture of said disc and release of the pressure in said space, and means engaging the outer margin of said disc to lock it securely to the casing.

References Cited in the file of this patent UNITED STATES PATENTS Egbert May 11, 1926 Ragland Jan. 22, 1952 Hill Dec. 2, 1952 Kolos .Tune 14, 1955 Chupa Apr. 15, 1958 FQREIGN PATENTS Great Britain May 22, 1924 

1. IN AN ACCUMULATOR HAVING A CASING, MEANS FOR CHARGING THE INTERIOR SPACE OF SAID CASING COMPRISING A RESILIENT, UNAPERTURED, PIERCEABLE PLUG OF SELF-SEALING MATERIAL, SAID CASING HAVING AN OPENING TO SAID SPACE RECEIVING SAID PLUG, SAID PLUG BEING ADAPTED TO BE PENETRATED BY A HYPODERMIC NEEDLE OR THE LIKE FOR SUCH CHARGING, A REMOVABLE RIGID DISC SECURED TO SAID CASING OUTWARDLY OF AND OVER SAID PLUG TO HOLD THE LATTER AGAINST OUTWARD DISTORTION OR DISPLACEMENT UNDER PRESSURE, SAID DISC HAVING AN APERTURE TO RECEIVE THE NEEDLE FOR CHARGING, AND A REMOVABLE CLOSURE FOR SAID APERTURE HAVING A PART SHAPED TO ENTER THE APERTURE AND ENGAGE THE PLUG, THE INNER SURFACE OF SAID PLUG BEING FLUSH WITH THE INNER SURFACE OF SAID CASING. 